This invention relates generally to retainer elements employed for securing objects in fixed relationship within a recess or receptacle. More particularly, the present invention relates to means for securing a vial of a level in a vial retaining recess.
Bubble vials are conventionally mounted in tools and instruments which incorporate a level indicator to thereby provide an efficient level indicating means. Cylindrical receiving recesses or receptacles are commonly formed in the body of the instrument for receiving the vial. The vial conventionally has a generally cylindrical exterior shape and is dimensioned to be closely received in the recess or receptacle. The vial is conventionally secured in fixed position by cementing the vial in position, filling the end of the receptacle with a hot melt adhesive, or otherwise closing one or more ends of the receiving receptacle. While the foregoing processes have proved satisfactory for securing the vial in position, the use of a mechanical retainer member presents certain advantages in term of assembly efficiency, aesthetics and quality control.
There are a multitude of mechanical fastener devices having a star-like, radially protruding ear configuration and which are adapted for securing an object in fixed position to a mounting structure. Parkin U.S. Pat. No. 3,007,726 discloses a fastening device which employs two series of resilient integral tongues. One series of the tongues extends toward a central aperture while the second series extends outwardly away from the aperture. The outer tongues are specifically adapted for engagement with the internal wall of a cavity to prevent withdrawal of the device from the cavity. The inner series of tongues is adapted to bite into a rod, such as an umbrella stick, which is inserted through the aperture.
Orain U.S. Pat. No. 3,320,846 employs a device having a quasi W-shaped cross-sectional configuration which includes a plurality of angularly spaced resilient arms which are inclined to the plane perpendicular to the axis of the device. The arms have sharp edges which cut into a bore defining surface when the retention device is rotated.
Maurer U.S. Pat. No. 2,798,748 discloses an annular clamping disc which has a single set of substantially identical spoke-like portions having a central rectangular slot. The clamping disc is adapted to engage an outer member for receiving a shaft. The disc functions as a key for non-rotatably securing elements to a rotary shaft.
Becker U.S. Pat. No. 2,670,226 discloses a fastening device which employs axially spaced sets of tongues and teeth. The support engaging tongues seat against the bottom of an opening so that the tongues engage the wall of the opening to retain the fastener in the opening. A second set of teeth is disposed at a second end of a hollow body portion. The teeth are inclined to facilitate engagement of the tongues with a tubular member so that the series of tongues engages the wall of an opening in a support and the other series of teeth is adapted to cooperatively interiorly engage the end of the tubular member which is inserted into the opening.
None of the noted patents disclose a retainer member which employs dual sets of ears wherein one set engages the wall of a receptacle to retain the retainer member in position and the other set resiliently engages an end of the object to be secured in position within the receptacle.